Dr. Deborah Jenkins

Long post worth the read. I have a close friend who flies private jets. He flew Lear 60 for over 15 years and now flies a Gulfstream. This is a copy and paste of his response to me asking him if he thought Ice was the issue. “We always fly in ridiculous cold temperatures.” “Usually you get the bad ice when the temperatures are like 0 to negative 20. Believe it or not, there's a point where it gets too cold for ice. At negative 40, you pretty much can't get ice. Besides that, the airplane is equipped with hot wings and hot tail.” “I flew the Lear 60 for like 15 years. It's a no joke airplane and probably the most dangerous airplane I've ever flown. It has a super critical wing. The airflow has to be perfect. When it gets into rough air and turbulence, it will easily stall. It has stalled on me at 41,000 feet just because we got into some turbulence. (On the way to Palm Beach as a matter of fact. ) we recovered and got her flying again around 30,000 ft. Scary But here's the problem. This airplane has a terrible coffin corner. (At high altitudes) what that means is, you fly in a really narrow window where if you lose 20 knots, it stalls. And if you gain 20 knots, it goes into overspeed. The air goes supersonic over the wing and it goes into a high speed stall, or worse, a Mach tuck. So if you stall, the normal recovery is to push the yoke forward to lower the nose and gain air speed again. At low altitude, you can push really hard and recover quickly. But in the 60... if you push hard, it will gain air speed and go into a high speed stall, it doesn't take much. It's very sensitive. The 60 has super short wings that don't make much lift. So then you high speed stall, and the computer is yelling at you... OVERSPEED! So then you pull back and enter a low speed stall. And you go back and forth trying to keep it in the air speed window. This whole thing is pretty scary. And you should recover basically by using your finger tips using super small corrections. You can't over do it. If you try to muscle the recovery, she gets mad and will become unrecoverable. If she enters a mach tuck. You're done.” “I taught the Lear 60 to other pilots and mentored them. I told them... this airplane has a soul and it's trying to kill you. Do not ever try to top the weather. Don't go over a thunderstorm. Go around it. If it means a half hour longer, then do it. Going over the thunderstorm will go into turbulence that you might not recover from. These pilots went right over a thunderstorm. I think it stalled which caused them to drop down into the thunderstorm and ended up in mach tuck. They picked up so much speed that it ripped off the horizontal stabilizer. At that point... chuck Yeager can't fix it. These same pilots did something similar a couple months ago. ATC got mad at them. They poked the bear one too many times. This is not a beginner airplane. The Gulfstream would never do this. It has HUGE margins of error and won't stall like that. But then again... it's got HUGE wings. It's a pussy cat. The Gulfstream is like driving a 4 wheeler. The Lear 60 is like riding a uni cycle.”